Hard disk drives and other electronic equipment are often placed within enclosures to provide a clean environment that is necessary for optimal operation of the equipment. For example, hard disk drives normally contain at least one inflexible platter or disk coated with magnetic material that is positioned within an enclosure. The disk is rapidly spun and a magnetic read/write head “flies” a few microns above it in order to access or store data. The magnetic head rides on an air cushion, and it is desirable to position the head as close as possible to the disk without touching it in order to provide a high capacity drive.
Contaminants, including particles, gases, and liquids within the hard disk drive enclosure can act to reduce the efficiency and longevity of the hard drive. These contaminants can gradually damage the drive, cause deterioration in performance, and in certain situations can even cause sudden and complete drive failure. Contaminants can either enter the electronic enclosure from an external source or be generated from within the enclosure during use. Common sources of contaminants in disk drives include leaks, which may or may not be intentional, the manufacturing environment, which can contain certain contaminants, and materials incorporated into the disk drive which give off particulates and gases.
One particular concern regarding electronic enclosures is that contaminants from outside of the electronic enclosure should be prevented from entering the enclosure. When a disk drive is in operation, the air in the drive enclosure heats up which creates an increase in air pressure in the enclosure. As a result of this increase in pressure, air escapes from the drive if it is not sealed airtight or if it has a breather hole. When a disk drive ceases to be in operation, the air in the enclosure cools down and creates a decrease in air pressure in the enclosure. As a result of this decrease in pressure, air moves into the drive. If particulate or chemical contaminants are present in this exchanged air, the interior of the enclosure will become contaminated.
Therefore, a need exists for a filter for use in an electronic enclosure, in particular a filter that prevents contaminants from entering the enclosure due to the exchange of air with the exterior environment.